Stem Borer and Leaf Folder in Paddy and Basmati: An Overview
Paddy and basmati are two important types of rice that are widely grown around the world. They are a staple food for millions of people and generate significant revenue for farmers and agribusinesses. However, the cultivation of these crops is often challenged by various pests and diseases that can significantly reduce their yield and quality. One such pest is the stem borer and leaf folder, which can cause severe damage to paddy and basmati crops. In this article, we will provide some essential information about these pests and how to manage them effectively.
Stem Borer
Stem borers are a group of insects that tunnel into the stems of rice plants, causing significant damage to the vascular tissues. There are several species of stem borers, but the most common ones that attack paddy and basmati are the yellow stem borer (Scirpophaga incertulas), the dark-headed stem borer (Chilo partellus), and the striped stem borer (Chilo suppressalis). The damage caused by stem borers results in empty panicles, delayed flowering, and ultimately, reduced grain yield.
Signs of Stem Borer Infestation
The key signs of stem borer infestation are wilting and drying of leaves, withered and broken apical shoots, and hollowed-out stems with slimy excreta. The adult moths of stem borers lay eggs on the lower side of leaves or stems, and the larvae feed on the inside of the stems, causing untold damage. The newly hatched larvae bore tunnels inside the stem, which results in wilting and dying-off of the affected tillers.
Management of Stem Borers
The management of stem borers involves several integrated control measures. These include cultural, biological, and chemical control measures. Cultural methods such as crop rotation and the use of resistant varieties can be effective in reducing infestation rates. Biological control using natural enemies like Trichogramma, a group of egg parasitoids, can also suppress the population of stem borers. Chemical control measures involve the use of insecticides such as cartap hydrochloride and chlorantraniliprole, which are effective against stem borers.
Leaf Folder
Leaf folders are another group of pests that attack rice plants. They are known to cause significant yield losses, especially in young and tender plants. Leaf folders are the larvae of a moth called Cnaphalocrocis medinalis, which folds the leaves and feeds on the mesophyll tissues. They are more prevalent in basmati varieties due to their longer stature and easy accessibility of tender leaves.
Signs of Leaf Folder Infestation
The key signs of leaf folder infestation are the folding of leaves, webbing of leaves, stunted growth, and the presence of excreta on the leaves. The larvae of the leaf folder fold young rice leaves and use silk webs to prevent them from unfurling. The folded leaves disrupt the photosynthesis process, leading to low grain yields.
Management of Leaf Folders
The management of leaf folders requires early detection and integrated pest management. Cultural methods such as deep plowing and the use of resistant varieties can control leaf folder infestations. Chemical control measures involve the use of insecticides, such as Indoxacarb, Emamectin Benzoate, and Lambda-Cyhalothrin. The timing of insecticide application is crucial to achieving effective control.
Conclusion
Stem borers and leaf folders are two important pests that affect the yield and quality of paddy and basmati crops. Early detection and integrated pest management are key to controlling these pests effectively. Farmers must use a combination of cultural, biological and chemical control measures to manage stem borers and leaf folders. By adopting sustainable pest management practices, farmers can protect their crops and ensure a steady supply of rice to the market.